Tube expander



June 2, 1931. l R. BUNGEROTH 1,808,531

` TUBE EXPANDER Original Filed VJuly 23. 1927l Patented June 2, 19,31

UNITED STATES vRIUDOIE' BUNGEBOTH, 0F DUSSLDORF, GERMANY v' TUBEEXPANDER Original application led July 23, 1927, Serial Io. 208,013, andin Germany .December 29, 1925. Divided .and this application ledDecember 17, 1927. Serial No. 210,884.

The invention relates to apparatus for expanding metal tubes withregular or varying thickness of wall, and is a division of my copendingapplication Serial No. 208,013, filed July 23rd, 1927, now Patent1,682,724.

l The expanding of tubes by inclined roller devices by the use of amandrel has been sev- ,eral times attempted. The arrangements hithertopreferably) used, in which the' mandrelLshafts are su j ected topressure, have given rise to considerable diiliculty since the mandrel,subjected to pressure, yields more or less in accordance with the degreeof the rolling pressure and accordingly alters its positicn relative tothe rollers.

The result is an irregular and uncommercial manufacture.

It has also been proposed to secure the mandrel to a shaft of themachine where y pressure on the mandrel or the-mandrel shaft is avoided.

However, in these machines also it is not possible to realize the maincondition for the production of a uniform product, .which conb sists inmaintaining the mandrel during the working period exactly in itsposition between the rollers.

'lhese defects of the known arrangemen have been particularly noticeablein the manufacture of tubes of considerable length, as

they are now generally required. "E

The present invention relates to machines in which the expanding iseffected by means of a mandrel which is secured to a mandrel shaftplaced on the inlet side of the machine v and it is differentiated fromthe known apparatus in that the mandrel shaft is adjustably arranged.

In this manner, it is possible to maintain the mandrel always in adefinite position between the rollers during the working period, andconsequently to compensate for 4any al teration of the mandrel shaft'. l

The adjusting means may bev of` any suitable kind. l

' A coarse or fine adjustment of the mandrel may be provided. In theimproved machine, the expanding of tubes of considerable length j 0 'andconstant dimensions presents no diilicul-` question of moving themandrel and tube corlaced at the inlet sideties as the mandrel alwaysmaintains its defimte position between the rollers.

The invention is illustrated by the accompanying drawings in which- Fire 1 is a longitudinal section showing one orm of the invention;

Fig. 2 is a longitudinal section showing another forml of the invention.

It has already been proposed to effect movement of a mandrel by means ofan hydraulic piston in rolling operations in which the mandrel andarticle Whichis being rolled are moved to correspond with the rollingoperation. In the present case it is not a responding to the rollingoperation, but rather one of giving' an absolutely definite position tothe mandrel relative to the rollers and retaining the mandrel in thisposition during the working period.

Two constructionsv embodying the inven tion are illustrated in thedrawings. Figure 1 shows a disc apparatus in plan view in which rollerdiscs a, which are relatively disposed in known manner, act inconjunction with the mandrel b to effect the expansion of the tube. rThe mandrel shaft c 1s in thisv case arranged on the entry side of theap aratus. To one end' of the mandrel shaft 1s secured the mandrel b,the other end being connected to an adjusting devicel which consists ofa piston rod 3, piston 4 andcylinder 5.l With this construction themandrel shaft is not subjected to a bending, but to a tensile stress.'In this manner even in the case of considerable lengths, which exceedthat of the tube to be produced by from about one `to two meters, aconsiderable lreduction in the cross sectional area of the mandrel shaftis effected, in contrast to the mandrel shafts heretofore-used whichhave been subjected to pressure, and, therefore, made very heavy withresulting inconvenience in handling. The mandrel shaft which issubjected to tension, does not alter its length '1n proportion to theroller pressure, and, therefore, retains dthe mandrel. in the ad-v ustedV'tion un er varying rassure.

l* In thldodlonstruetion illustrate in Figure 1 vthe mandrel shaft cisoonneeted to one end 109 so I of the piston rod 3. The other end ofthe piston ro moves' in the cylinder 5' in known manner.

Pipes 6 and'7 are rovided at the ends of the cylinder 5 throug whichpressure may be transmitted to the cylinder by means of a fluid, whichmay he hquid or gaseous. Suitable known controls may be providedwherepiston may be accurately regulated and an absolutely definiteposition thereby given the mandrel.' It is evident that the mandrelosition may be maintained by the means just described or that if themandrel shaft should have altered its length because of heat during therolling, the position of the mandrel may be readjusted during therolling.

If a 1particularly ine adjustment'of the mandre is required asupplementary ne adjustment means may'be provided.

Fig. 2 illustrates iuidV actuated means for giving the mandrel coarseadjustment, to which is added other means for giving fine adjustment. Inthis case a screw spindle, worm wheel, worm, and hand-wheel areillustrated as giving the iine adjustment.

arrangement is here shown which is somewhat similar to that illustratedin Fig.- ure 1. A mandrel b is fastenedto one end of a mandrel shaft lcwhich is arranged on the entry side of the apparatus. The other end ofthe mandrel shaft, as in Figure 1', is connected to an adjusting devicewhich consists primarily of a piston'rod 31, piston 4 and cylinder 5.

Instead of attaching the mandrel shaft directl to the ,-piston rod as isthe case in the examp e illustrated in Figure 1, in the present case themandrel shaft is connected to one end of a stem 8 whose other end 9 isexpanded and threaded. The threaded end 9 of the' stem 8 turns within aflanged nut 10, with whose internal threads it engages. The piston rod31 is extended beyond thev piston4 away from the mandrel and Ycontains abore into which lthe nut 10 extends and in which the nut is free torotate. lThe nut 10 has a flange 11 which bears on one side against 'ashoulder 12 formed on the piston rod 31,

and on the other side against a plate 13 spaced `from the shoulder 12.'Thus, while the nut is free'to rotate in the bore of the piston lrod 1tis constrained against axial movement with to the piston rod.

to the flanged nut 10 and serves torotate it. A worm 15, upon whoseshaft 16 is ahandwheel 17, provides means for operating the worm wheeland with itthe nut 10.Y Ihus the 3 is connected with the piston 4, whichthe fluid pressure on both sides of the eglitere shown, a worm wheel 14is attached Bymeans of the present invention it is therefore possible tomaintain the mandrel always in a definite position between the roll'-adjust the` mandrels 'position during the working period to compensatefor any alteration in the length ofthe mandrelshaft.

I claim:

1. In apparatus for expanding metal tubes, a mandrel shaft located atthe inlet side of the apparatus, anda mandrel carried by said shaft, incombination with iuid actuated means forgiving rough adjustment to saidmandrel during rolling, and other means axially movable with saidluidactuated means and mandrel shaft for giving fine adjustment t0 saidmandrel.

2. In apparatus for expanding metal tubes, a mandrel shaft located atthe inlet side of the apparatus, and a mandrel carried by said shaft, incombination with fluid actuated means for giving rough adjustment tosaid mandrel during rolling, and screw means' axially movable with saidfluid actuated means and mandrel shaft for giving fine adjustment tosaid mandrel.

3. In apparatus for expanding metal tubes, a fluid cylinder mounted atthe inlet side of the apparatus, a piston reciprocable therein, amandrel shaft, a mandrel carried lers during the working period, andalso t0 by the mandrel shaft, means connecting said v piston and mandrelshaft, and means for re ulating fluid pressure in the cylinder on botSides of the piston to position the mandrel and to maintain the mandrelin adjusted positions during expansion of the tube.

4. In apparatus for expanding metal tubes, a fluid cylinder .mounted atthe inlet side of the apparatus, a Liston reciprocable therein, amandrel shaft, a mandrel carried by the mandrel shaft, means connectingsaid piston and mandrel shaft, and means for regulating fluid pressureinthe cylinder on both sides ofthe piston for giving rough adjustment tosaid mandrel, and other means associated with .the piston and mandrelshaft forgiving fine adjustment to the mandrel.

In testimony whereof I vhave signed my 60 threaded end 9 of the stem 8is moved longitudinally of the piston rod and piston, and

the mandrel is given fine adjustment.

Thecylinder may be varranged pivotally to facilitate connectin anddisconnecting the plston rod and man rel shaft.

